1. Field of the Invention
The present invention is directed to toilet flushing. It finds particular application in tank-type flushers.
2. Background Information
Toilet flushers come in a wide arrange of designs. (We use the term toilet here in its broad sense, which encompasses what are variously referred to as toilets, water closets, urinals, etc.) Many designs are of the gravity type, which uses the pressure that results from the weight of water stored in a tank to flush the bowl and provide the siphoning action by which the bowl""s contents are drawn from it. Any flusher of this type employs a main flush valve, which controls the release of water from the tank through the tank outlet that leads to the bowl. For the flusher to act effectively, that flush valve must remain open long enough to let the required amount of water flow from the tank into the bowl.
A popular way of achieving the proper flush-valve-opening duration is to employ a pivoting flush valve on which a timer cup is disposed. The valve is pivoted to unseat it, and water in the full flush tank fills the timer cup. This so weights the cup that it keeps the valve pivoted to the open position. An orifice in the timer cup allows water to leak from it when the tank level has fallen below that of the timer cup. After a length of time great enough to allow most of the liquid to drain from the timer cup, the flush valve then pivots back into its closed position.
Another popular approach, typically used in automatic toilets, is to use a timer circuit to time activation of a solenoid that controls the flush valve""s operation. An advantage of many such installations is that they use line pressure to operate the flush valve and can therefore be arranged so that the flush valve seals more effectively than the typical manual flusher""s.
Commonly assigned copending U.S. patent application Ser. No. 09/716,870 filed on Nov. 20, 2000, by Parsons et al. for a Timed Fluid-Linked Flush Controller and hereby incorporated by reference describes an approach to flush-duration control that does not require electrical timing circuitry and yet lends itself to more-effective flush-valve operation than most manually operated flush valves customarily afford. That approach employs a valve-operating mechanism of the type in which water-line pressure is admitted into a control chamber whose resultant pressure can be relieved through a control-chamber pressure-relief outlet. The flush valve seats very effectively because pressure in a control chamber holds the flush valve seated when the line pressure prevails in it. When that pressure is relieved, the valve opening mechanism opens the flush valve.
In the mechanism described in that application, the pressure is relieved by a pressure-relief valve disposed at a remote location and interposed in a pressure-relief conduit that extends from the control chamber""s pressure-relief outlet to the remote location. When the remote valve is closed, it permits flow from the pressure-relief conduit and thereby prevents pressure relief in the control chamber. It is operable by manual depression from the closed state to an open state, in which it permits such a flow and therefore relieves pressure within the control chamber.
The way in which adequate flushing flow is ensured is that the remote valve is of the type that mechanically imposes a time delay between the user""s releasing the push button and the remote valve""s closing.
We have developed a particularly beneficial approach to the mechanical delay imposition. This approach employs a fluid linkage between a push button that the user depresses and a valve member that seals and unseals to control flow through the pressure-relief conduit. The fluid linkage is provided by an actuator chamber filled with an incompressible fluid. The chamber is defined by opposed movable walls respectively coupled to the push button and valve member. By pushing the button, the user displaces one wall and thereby causes the incompressible fluid and thus the wall coupled to the valve member. This displaces the valve member to an unseated position and thus permits pressure-relieving flow in the pressure-relief conduit.
In flowing to displace the valve member in the direction that causes it to unseal, at least part of the incompressible fluid flows through a check valve arranged to permit flow in that direction. When the user releases the push button, the actuation-chamber walls tend to return to rest positions, to which they are biased, but the check valve is arranged not to permit incompressible-fluid flow in the resultant direction. That flow must therefore occur through an alternate, higher-flow-resistance path. This imposes the delay needed to allow enough flushing flow, yet the check valve provides relatively low resistance in the forward path so that the user can push the button easily.
In one embodiment of this invention, the push-button assembly includes two different button members. The first of the button members is coupled to the actuation-chamber wall, while the second is so mounted as to bear against the first button member, and thereby cause the valve to open, when the user presses on the second one. The second button member""s mounting also permits only a relatively small amount of travel, so the actuation-chamber displacement results in only a relatively short valve-operation delay and thus a relatively small flushing flow. If the user desires a more-complete flushing flow, he directly presses the first button member, which is so mounted as to permit more travel. This results in greater displacement of the actuation-chamber walls and therefore a longer delay in the valve member""s return.
Preferably, the valve members are mounted in a frame that forms a plurality of guides that permit different amounts of travel, and the button members can selectively be mounted in different ones of the guides to provide different delays for different installations.